I have a stupid theory for what Dark Matter really is, it is just a thought that crossed my mind a few days ago, I am just curios to know if anyone has ever thought of this in the past.

The good thing about the theory is that it is easy to prove or to falsify (it probably has been falsified, who knows) I just what to share it. and well obviously with "theory" I simply mean "a guess"

So what is dark matter?

It is assumed that gravity and light travel at the same speed, but that assumption has never been proven with certainty, it could be that gravity (gravitational waves) travel slightly slower than the speed of light.

If this where true, then the light that we see form distant galaxies is younger than the gravity that we can detect, when we see a distant galaxy 1,000,000,000 light years away, we see light that is 1,000,000,000 years old, but we detect gravity that is older than that (say 10,000,000 years older)

dark matter is simply the gravity of dead stars, we can not see their light but we can detect their gravity. if a star died 1,000,000,001 years ago we would no see the star, it but we could detect its gravity.

the theory is very easy to prove or to falsify, just find a galaxy that is 1,000,000,000 light years away, based on model of stellar evolution, we could predict how many stars where there 1,000,000,000 years ago and 1,000,000,010 years ago, if the differential of stars accounts for the mass attributed to dark matter, the theory would be correct, if not it would be falsified. ...........

brief summery.in a galaxy that is 1,000,000,000 away

if a star died 1,000,000,001 years ago, we would not see its light, but we would detect its gravity (assuming that gravitational waves travel slower than light) maybe dark matter is simply that gravity.

I like this line of thought, but I think I see a couple errors and likely others will be able to go into more depth. The biggest one, though, is that when a star dies it's not like you flip a switch and the light goes off. There's still something detectable, from a white dwarf to a neutron star to a black hole. "Dead" stars still give off detectable radiation, they don't just vanish.

We can see the rotation curves of galaxies quite close to us, and they fit the dark matter profile.

Also, the speed at which gravity propagates is a done deal, and was measured indirectly as far back as 2002. Moreover, we should actually expect gravitational waves to arrive earlier than the light, because light is slowed down in different mediums, while everything is transparent to gravity, so gravity should cover the intervening distance quicker, on average.

An interesting idea, but pretty much falls over when you consider physics.

Grumpy Santa wrote:I like this line of thought, but I think I see a couple errors and likely others will be able to go into more depth. The biggest one, though, is that when a star dies it's not like you flip a switch and the light goes off. There's still something detectable, from a white dwarf to a neutron star to a black hole. "Dead" stars still give off detectable radiation, they don't just vanish.

call it a star, supernova, white dwarft neutron star.......etc. the point is that at some point there would be a "last detectable photon" after that moment there would still be gravitational waves for a few million years.

We can see the rotation curves of galaxies quite close to us, and they fit the dark matter profile.

Also, the speed at which gravity propagates is a done deal, and was measured indirectly as far back as 2002. Moreover, we should actually expect gravitational waves to arrive earlier than the light, because light is slowed down in different mediums, while everything is transparent to gravity, so gravity should cover the intervening distance quicker, on average.

An interesting idea, but pretty much falls over when you consider physics.

well before posting this "theory" I did some reading and found out that the door is still open of the possibility that Gravitation Waves and photons travel at a different speed

The rate of this damping can be computed, and one finds that it depends sensitively on the speed of gravity. The fact that gravitational damping is measured at all is a strong indication that the propagation speed of gravity is not infinite. If the calculational framework of general relativity is accepted, the damping can be used to calculate the speed, and the actual measurement confirms that the speed of gravity is equal to the speed of light to within 1%. (Measurements of at least one other binary pulsar system, PSR B1534+12, confirm this result, although so far with less precision.)

As far as I can tell, it doesn't really matter which one is faster than the other, as long that there is a meaningfull difference between speeds it would follow that the mass that we "see" does not correspond to the gravity that we can detect.

the only flaw I was capable of detecting is that if this theory where true, we would expect to see a pattern,........... close galaxies would have more less the same amount of darkmatter, with respect to each other, and distant galaxies would have big differences. ..........if this where true scientists would have publish this pattern long ago

leroy wrote:well before posting this "theory" I did some reading and found out that the door is still open of the possibility that Gravitation Waves and photons travel at a different speed

The rate of this damping can be computed, and one finds that it depends sensitively on the speed of gravity. The fact that gravitational damping is measured at all is a strong indication that the propagation speed of gravity is not infinite. If the calculational framework of general relativity is accepted, the damping can be used to calculate the speed, and the actual measurement confirms that the speed of gravity is equal to the speed of light to within 1%. (Measurements of at least one other binary pulsar system, PSR B1534+12, confirm this result, although so far with less precision.)

Well, the difference between being able to find an article that you think supports your view and actually understanding the underlying physics is that, with the latter, it's trivial to spot that the article doesn't say anything remotely like your palsied formulation of it. It doesn't even approach saying that they travel at different speeds.

As far as I can tell, it doesn't really matter which one is faster than the other, as long that there is a meaningful difference between speeds it would follow that the mass that we "see" does not correspond to the gravity that we can detect.

No, it really wouldn't, and you still have all your work ahead of you to show that gravity can propagate slower than light.

the only flaw I was capable of detecting is that if this theory where true, we would expect to see a pattern,........... close galaxies would have more less the same amount of darkmatter, with respect to each other, and distant galaxies would have big differences. ..........if this where true scientists would have publish this pattern long ago

Well, your ability to detect flaws aside, along with repeating that what you have is not a theory, this might be the first sensible thing you've said on this forum, even if it is nothing more than a repeat of what I'd already said above.

hackenslash wrote:[Well, the difference between being able to find an article that you think supports your view and actually understanding the underlying physics is that, with the latter, it's trivial to spot that the article doesn't say anything remotely like your palsied formulation of it. It doesn't even approach saying that they travel at different speeds.[

No, what the article states is that the speed of gravity has not been measured independently, meaning that it could be different from the speed of light, ..............but granted, I don't claim to understand the physics of relativity and gravity, this is why I shared my "theory". I am expecting to learn from all your comments.